class_docstr: [summary]
  
  Args:
    test {[type]} -- [description]
docstr: Test write/read file.
docstr_tok: ["Test","write\/read","file","."]
code: def test_write_read_file(self):
      """Test write/read file."""
      # Setup and check preconditions.
      file_name = self._path_to("writereadfile")
      if tf.io.gfile.exists(file_name):
          tf.io.gfile.remove(file_name)
  
      # Write data.
      with tf.io.gfile.GFile(file_name, "w") as w:
          w.write("Hello\n, world!")
  
      # Read data.
      with tf.io.gfile.GFile(file_name, "r") as r:
          file_read = r.read()
          self.assertEqual(file_read, "Hello\n, world!")
  
imports: import os
  import subprocess
  import sys
  import pytest
  import tensorflow
  import tensorflow_io
label_desc: Use image node_id 6 for calling the AZFSTestBase obj's underlying member method code with example usage: obj.test_write_read_file() without return types